All-plastic hand-assembled super-strength reverse osmosis membrane housing

Abstract

A cylindrical central high-strength pipe, normally a custom extrusion of PVC, mounts caps, preferrably of high-strength Rhinite™ plastic, at both ends so as to create an interior reservoir that is capable of being pressurized to a working pressure of 230 P.S.I. and a burst pressure in excess of 600 P.S.I. Each end cap, permanently affixed to the pipe end by gluing, includes a cylindrical outer sleeve extending beyond the pipe end and presenting in its extension a circular interior groove. A circular plug, again preferably made from Rhinite™ plastic, is inserted into the sleeve extension to form a pressure tight seal against a circular gasket, preferably a robust one eight inch (1/8") thickness "O"-ring. A retaining ring, preferably made of Delrin™ plastic, that is expandable and contractible in circumference is inserted in the circular interior grove of the sleeve and against the plug, therein to make that the reservoir is capable of being pressurized. Complimentary beveled surfaces on the plug and the retaining ring serve to forcibly hold both in position against pressure forces within the reservoir.

What is claimed is: 
     
       1. In a membrane housing having a cylindrical central pipe and caps to the pipe ends so as to create a reservoir within the interior of the pipe that is capable of being pressurized, an improvement wherein at least one of the caps comprises: a cylindrical outer sleeve permanently affixed to a pipe end and extending beyond the pipe end, the sleeve presenting in its extension a circular interior groove;   a circular gasket within the cylindrical sleeve;   a circular plug inserted into the sleeve extension to form a pressure tight seal against the gasket, the circular plug having and presenting at its circular periphery opposite to the seal a bevel surface; and   a retaining ring inserted in the circular interior grove of the sleeve and against the plug in a plug position outboard of the reservoir so as to hold the plug in the sleeve, the retaining ring seating upon the bevel surface of the circular plug in a manner that tends, when a pressure force is exerted on the plug such as would tend to eject the plug from the sleeve, to force the retaining ring to greater circumferential distension, and into the circular interior grove of the sleeve into which the retaining ring fits;   wherein pressure in the reservoir tends to hold the retaining ring in its place within the groove.   
     
     
       2. The membrane housing according to claim 1 wherein each of the cylindrical outer sleeve, the circular plug and the retaining ring are plastic.   
     
     
       3. The membrane housing according to claim 1 wherein the retaining ring seated upon the bevel surface has and presents a cylindrical flange extending in parallel with a cylindrical interior surface of the cylindrical sleeve, the flange further tending to stabilize the retaining ring in its place within the groove.   
     
     
       4. The membrane housing according to claim 3 wherein the retaining ring has and presents a small opening by which the ring may be foreshortened in diameter and circumference so as to facilitate insertion into and extraction from the groove; and   a feature, located towards the interior of the retaining ring at the location of its opening, suitable to be grasped by the fingers in order that when the retaining ring is located in the grove then it is manually extracted therefrom.   
     
     
       5. A housing for the membrane of a reverse osmosis system comprising: a cylindrical central pipe having ends;   a sleeve permanently affixed to an end of the pipe and extending beyond the pipe end, the sleeve presenting in its extension a circular interior groove;   a circular plug inserted into the sleeve extension so as to have one circular surface facing outward, and one circular surface facing inward, to the pipe, the circular plug having and presenting at a circular periphery of its outward-facing circular surface a bevel surface; and   a retaining ring, having a bevel surface that is complimentary to the bevel surface of the plug, inserted in the circular interior grove of the sleeve and seating, bevel surface to bevel surface, against the plug so as to hold the plug in the sleeve., the seating tending, when any force is exerted on the plug as would tend to expel the plug outward from its held position within the sleeve, to force the retaining ring to greater circumferential distension, and tightly into the circular interior grove of the sleeve into which the retaining ring fits.   
     
     
       6. A manual method of removing an old membrane filter and inserting a new membrane filter within a pressurized membrane housing of a reverse osmosis system, the method comprising: de-pressurizing a reservoir, defined by a cylindrical central pipe and caps to the pipe ends, containing the old membrane filter;   foreshortening by force of the fingers a retaining ring, located in a circular interior groove of an end cap, that has and presents (i) a peripheral bevel, and a small opening by which the ring may be so foreshortened in diameter and circumference, and extracting the retaining ring from the groove;   extracting a circular plug, also having a peripheral bevel, from the end cap so as to obtain access to the interior of the cylindrical central pipe;   removing the old membrane filter, now exposed by extraction of the beveled circular plug, from its position within the interior of the cylindrical central pipe;   inserting a new membrane filter into position within the interior of the cylindrical central pipe;   replacing the beveled circular plug within the end cap so that its peripheral bevel is outward facing;   replacing the foreshortened retaining ring into the circular interior groove of the end cap so that its peripheral bevel contacts against the peripheral bevel of the circular plug, permitting the retaining ring to expand once in position within the groove; and   re-pressurizing the reservoir, now containing the new membrane filter., so that the circular plug to the reservoir is forced outward against the retaining ring in a manner that, by operation of the contacting bevels of the plug and of the retaining ring, forces the retaining ring so tightly within the groove that it can no longer be foreshortened and extracted by force of the fingers;   wherein the membrane filter is manually replaceable within the membrane housing of a reverse osmosis system, but only when the membrane housing is de-pressurized.   
     
     
       7. A method of making a membrane housing of a reverse osmosis system, the method comprising: cut and machine both ends of a plastic pipe suitable to define a cylindrical reservoir holding an osmosis membrane;   prepare both cut and machined pipe ends for bonding;   bond a cylindrical sleeve having an internal circumferential groove to each pipe end so that a portion of the cylindrical sleeve including its internal circumferential groove extends beyond each pipe end;   prepare plugs suitable to fit within the cylindrical sleeve at each pipe end, each plug having and presenting a peripheral bevel surface, and insert a beveled plug within the cylindrical sleeve at each pipe end;   install a retaining ring, the retaining ring having and presenting a peripheral bevel surface that is complimentary to the bevel surface of the beveled plug, within the cylindrical sleeve at each pipe end so as to fit against the plug, bevel surface to bevel surface, and so as to retain the plug within the cylindrical sleeve;   wherein the bevel surface of the plug forces against the bevel surface of retaining ring in a manner that tends, when any force tend to eject the plug from the sleeve is exerted on the plug, to force the retaining ring to greater circumferential distension, and tightly into the circular interior grove of the cylindrical sleeve into which the retaining ring fits.   
     
     
       8. A housing for the membrane of a reverse osmosis system comprising: a cylindrical member suitable to receive the membrane of a reverse osmosis system, the cylindrical member having and presenting ends and also a circular interior groove near at least one end;   a circular plug, having opposed circular surfaces, inserted into at least that one end of the cylindrical member near to which end is presented the interior circular groove so as to have one of its circular surfaces facing outward from, and the other one of its circular surfaces facing inward to, the cylindrical member, the circular plug having and presenting at a circular periphery of its outward-facing circular surface a bevel; and   a retaining ring, having a bevel that is complimentary to the bevel of the plug, inserted in the circular interior grove of the cylindrical member and seating, bevel to bevel, against the plug so as to hold the plug in the cylindrical member;   wherein the seating, plug bevel to retaining ring bevel, tends, when any force is exerted on the plug as would tend to expel the plug outward from its held position within the cylindrical member, to force the retaining ring to greater circumferential distension, and tightly into the circular interior grove of the cylindrical member into which the retaining ring fits.